command.c revision 5a0e3ad6af8660be21ca98a971cd00f331318c05 
1
2/*
3 * IBM ASM Service Processor Device Driver
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 *
19 * Copyright (C) IBM Corporation, 2004
20 *
21 * Author: Max Asb�ck <amax@us.ibm.com>
22 *
23 */
24
25#include <linux/sched.h>
26#include <linux/slab.h>
27#include "ibmasm.h"
28#include "lowlevel.h"
29
30static void exec_next_command(struct service_processor *sp);
31
32static atomic_t command_count = ATOMIC_INIT(0);
33
34struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
35{
36	struct command *cmd;
37
38	if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
39		return NULL;
40
41	cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
42	if (cmd == NULL)
43		return NULL;
44
45
46	cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
47	if (cmd->buffer == NULL) {
48		kfree(cmd);
49		return NULL;
50	}
51	cmd->buffer_size = buffer_size;
52
53	kref_init(&cmd->kref);
54	cmd->lock = &sp->lock;
55
56	cmd->status = IBMASM_CMD_PENDING;
57	init_waitqueue_head(&cmd->wait);
58	INIT_LIST_HEAD(&cmd->queue_node);
59
60	atomic_inc(&command_count);
61	dbg("command count: %d\n", atomic_read(&command_count));
62
63	return cmd;
64}
65
66void ibmasm_free_command(struct kref *kref)
67{
68	struct command *cmd = to_command(kref);
69
70	list_del(&cmd->queue_node);
71	atomic_dec(&command_count);
72	dbg("command count: %d\n", atomic_read(&command_count));
73	kfree(cmd->buffer);
74	kfree(cmd);
75}
76
77static void enqueue_command(struct service_processor *sp, struct command *cmd)
78{
79	list_add_tail(&cmd->queue_node, &sp->command_queue);
80}
81
82static struct command *dequeue_command(struct service_processor *sp)
83{
84	struct command *cmd;
85	struct list_head *next;
86
87	if (list_empty(&sp->command_queue))
88		return NULL;
89
90	next = sp->command_queue.next;
91	list_del_init(next);
92	cmd = list_entry(next, struct command, queue_node);
93
94	return cmd;
95}
96
97static inline void do_exec_command(struct service_processor *sp)
98{
99	char tsbuf[32];
100
101	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
102
103	if (ibmasm_send_i2o_message(sp)) {
104		sp->current_command->status = IBMASM_CMD_FAILED;
105		wake_up(&sp->current_command->wait);
106		command_put(sp->current_command);
107		exec_next_command(sp);
108	}
109}
110
111/**
112 * exec_command
113 * send a command to a service processor
114 * Commands are executed sequentially. One command (sp->current_command)
115 * is sent to the service processor. Once the interrupt handler gets a
116 * message of type command_response, the message is copied into
117 * the current commands buffer,
118 */
119void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
120{
121	unsigned long flags;
122	char tsbuf[32];
123
124	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
125
126	spin_lock_irqsave(&sp->lock, flags);
127
128	if (!sp->current_command) {
129		sp->current_command = cmd;
130		command_get(sp->current_command);
131		spin_unlock_irqrestore(&sp->lock, flags);
132		do_exec_command(sp);
133	} else {
134		enqueue_command(sp, cmd);
135		spin_unlock_irqrestore(&sp->lock, flags);
136	}
137}
138
139static void exec_next_command(struct service_processor *sp)
140{
141	unsigned long flags;
142	char tsbuf[32];
143
144	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
145
146	spin_lock_irqsave(&sp->lock, flags);
147	sp->current_command = dequeue_command(sp);
148	if (sp->current_command) {
149		command_get(sp->current_command);
150		spin_unlock_irqrestore(&sp->lock, flags);
151		do_exec_command(sp);
152	} else {
153		spin_unlock_irqrestore(&sp->lock, flags);
154	}
155}
156
157/**
158 * Sleep until a command has failed or a response has been received
159 * and the command status been updated by the interrupt handler.
160 * (see receive_response).
161 */
162void ibmasm_wait_for_response(struct command *cmd, int timeout)
163{
164	wait_event_interruptible_timeout(cmd->wait,
165				cmd->status == IBMASM_CMD_COMPLETE ||
166				cmd->status == IBMASM_CMD_FAILED,
167				timeout * HZ);
168}
169
170/**
171 * receive_command_response
172 * called by the interrupt handler when a dot command of type command_response
173 * was received.
174 */
175void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
176{
177	struct command *cmd = sp->current_command;
178
179	if (!sp->current_command)
180		return;
181
182	memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
183	cmd->status = IBMASM_CMD_COMPLETE;
184	wake_up(&sp->current_command->wait);
185	command_put(sp->current_command);
186	exec_next_command(sp);
187}
188